On Fri, Mar 12, 2010 at 09:55:07PM +0100, Willy Tarreau wrote:
> I've just looked at your traces. It's strange that it's related to the
> blackhole feature because the doc says it just disables sending of
> port unreachables (and possibly RSTs). From your traces, an RST is
> properly sent in response to the "250", but the server happily
> ignores despite the fact that its sequence number is OK, and it
> keeps resending the same data over and over. And as your trace
> shows that you sniffed on the server, there's no risk that the
> RST was dropped on the network.

After a bit of thinking, while it is wrong from the server to have
ignored the RST in the first place, it's wrong for the client not
to resend it on subsequent packets, and this is what is caused by
the BLACKHOLE patch. I've checked the patch, and I see what is
wrong in it : it prevents sending of RST packets in any case,
while it should only be prevented in response to a SYN. I have one
similar patch in my own 2.4 tree which does not exhibit the issue,
so I'll contact Brad with that.

Regards,
Willy


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